IETF Logo Mail Archive

Re: [dhcwg] RFC3315 and Hop Limit

Michael Richardson <mcr+ietf@sandelman.ca> Wed, 22 October 2014 16:43 UTC

Return-Path: <mcr@sandelman.ca>
X-Original-To: dhcwg@ietfa.amsl.com
Delivered-To: dhcwg@ietfa.amsl.com
Received: from localhost (ietfa.amsl.com [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id A36811ACDDA for <dhcwg@ietfa.amsl.com>; Wed, 22 Oct 2014 09:43:28 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.301
X-Spam-Level:
X-Spam-Status: No, score=-1.301 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, J_CHICKENPOX_92=0.6, SPF_PASS=-0.001, T_RP_MATCHES_RCVD=-0.01, T_TVD_MIME_NO_HEADERS=0.01] autolearn=no
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id QxNB0leD6z92 for <dhcwg@ietfa.amsl.com>; Wed, 22 Oct 2014 09:43:27 -0700 (PDT)
Received: from tuna.sandelman.ca (tuna.sandelman.ca [IPv6:2607:f0b0:f:3:216:3eff:fe7c:d1f3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 2A87C1ACDCC for <dhcwg@ietf.org>; Wed, 22 Oct 2014 09:43:26 -0700 (PDT)
Received: from sandelman.ca (obiwan.sandelman.ca [209.87.249.21]) by tuna.sandelman.ca (Postfix) with ESMTP id 34036200A7; Wed, 22 Oct 2014 12:44:05 -0400 (EDT)
Received: by sandelman.ca (Postfix, from userid 179) id 73E4263A84; Wed, 22 Oct 2014 12:43:10 -0400 (EDT)
Received: from sandelman.ca (localhost [127.0.0.1]) by sandelman.ca (Postfix) with ESMTP id 627A763A21; Wed, 22 Oct 2014 12:43:10 -0400 (EDT)
From: Michael Richardson <mcr+ietf@sandelman.ca>
To: Ralph Droms <rdroms.ietf@gmail.com>
In-Reply-To: <B9BCD98C-990B-4F13-AD88-014C4711BB2E@gmail.com>
References: <4117.1413928434@sandelman.ca> <B9BCD98C-990B-4F13-AD88-014C4711BB2E@gmail.com>
X-Mailer: MH-E 8.2; nmh 1.3-dev; GNU Emacs 23.4.1
X-Face: $\n1pF)h^`}$H>Hk{L"x@)JS7<%Az}5RyS@k9X%29-lHB$Ti.V>2bi.~ehC0; <'$9xN5Ub# z!G,p`nR&p7Fz@^UXIn156S8.~^@MJ*mMsD7=QFeq%AL4m<nPbLgmtKK-5dC@#:k
MIME-Version: 1.0
Content-Type: multipart/signed; boundary="=-=-="; micalg="pgp-sha1"; protocol="application/pgp-signature"
Date: Wed, 22 Oct 2014 12:43:10 -0400
Message-ID: <10209.1413996190@sandelman.ca>
Sender: mcr@sandelman.ca
Archived-At: http://mailarchive.ietf.org/arch/msg/dhcwg/n0LdDUf7I7CIkcACeHzHY5q5Te8
Cc: dhcwg <dhcwg@ietf.org>
Subject: Re: [dhcwg] RFC3315 and Hop Limit
X-BeenThere: dhcwg@ietf.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: <dhcwg.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/dhcwg>, <mailto:dhcwg-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/dhcwg/>
List-Post: <mailto:dhcwg@ietf.org>
List-Help: <mailto:dhcwg-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/dhcwg>, <mailto:dhcwg-request@ietf.org?subject=subscribe>
X-List-Received-Date: Wed, 22 Oct 2014 16:43:28 -0000

Ralph Droms <rdroms.ietf@gmail.com> wrote:
    >> I could not find any advice in RFC3315 as to what to set the IPv6 HOP
    >> Limit to for multicast'ed DHCPv6 messages.
    >>
    >> I would have thought that the sender should set it to 255, and the
    >> sender should validate that it is 255, to be sure that it's onlink.
    >> This is what mDNS/Bonjour does, but maybe 3315 predates that thinking.

    > I don't think the 255 hop count limit from RFC 6762 applies.  RFC 6762
    > mentions the use of the 255 hop count limit, but only for backward
    > compatibility.  RFC 6762 does not mandate the use of the 255 hop count

Ah, I know that we argued back and forth about whether or not HOP Limit=1,
or HOP Limit=255 was a better way to keep things link-local, and I was
surprised upon examining 3315 that there was no talk at all about that,
then I realized that it predated that discussion.

I'd always figured that if someone was going to screw up routing so much,
as to wind up forwarding multicast is if it was unicast, that they likely
also didn't decrement the TTL either....

--
Michael Richardson <mcr+IETF@sandelman.ca>, Sandelman Software Works
 -= IPv6 IoT consulting =-

v2.23.0 | Report a Bug | By Email